1. Field of the Invention
The present invention relates to cleaning methods and substrate processing apparatuses.
2. Description of the Related Art
Plasma processing apparatuses that perform predetermined plasma processing such as etching on substrates such as wafers for semiconductor devices using plasma are widely known as substrate processing apparatuses.
The plasma processing apparatus includes, for example, a process chamber in which a plasma is generated, an upper electrode and a lower electrode provided to face each other, and a gas supply part that supplies a process gas into a space between the upper electrode and the lower electrode through gas supply holes. High-frequency electric power is applied to at least one of the upper electrode and the lower electrode provided to face each other, and a process gas is excited by the electric field energy to generate a plasma, so that plasma processing is performed on a substrate with the generated discharge plasma.
In the case of using a depositive reaction gas as a process gas in the plasma processing apparatus, a reaction product generated from the process gas adheres to the internal surfaces (inner walls) of the process chamber and the gas supply holes. The adhesion of the reaction product causes a manufactured semiconductor device to be defective because of the adhesion of particles and causes a failure of the plasma processing apparatus. Therefore, as illustrated in, for example, Japanese Laid-Open Patent Application No. 2007-214512, a cleaning process for removing the reaction product that has adhered to the inside of the process chamber is performed at regular intervals.